WHY?Because
I just can't leave well enough alone, that's why. No matter how
good my vehicle may be, it can always be better. Many reviewers
have pointed out that the Colorado, tuned for maximim fuel economy, has
a relatively slow throttle response and a transmission that tends to
prefer higher gear ratios. Neither issue is a deal-breaker for
me, but I figure that overall driveability would be improved without
those two issues. Fortunately, both can be remedied by a good
tuner; as a bonus, horsepower and torque can also be increased.
I have experience with both custom tuners (a qualified technician
writes new parameters for an individual vehicle) and with "canned"
tunes (a tune written for a specific tytpe of vehicle). If I were
looking for maximum gains for a performance car I would use a custom
tuner, but since I'm just looking for improvement in driveability I
decided to go with a reputable aftermarket tuner.

Several
years ago I had excellent results from a DiabloSport Predator tuner on
a Ford truck, so when I heard that they had performace tunes for the
new Colorado I decided to give them a try. Their new handheld
programmer (l1000 InTune) is preloaded with tunes for many cars and
trucks, including the Colorado, so I decided to give it a try. The
InTune is carried by many aftermarket retailers, so you might want to
shop around. I found the best deal at Autoanything.com, including
an online coupon for 15% off. The total, with shipping, was $289
so I ordered and paid by credit card.

SERVICE: Excellent.
Immediately after placing the order I received an email
confirmation. I ordered during the Christmas season so I expected
to process to be slow but within 2 days I received a shipping
notification, complete with a tracking number. The tuner
arrived just four working days after I first
placed my order. I consider that to be pretty darned good
service. The tuner arrived double-boxed, and everything was in
good order. The programmer was packed with a USB cable for
updates, a cable to connect it to the OBD port, and an excellent set of
directions.

INSTALLATION: Not
too difficult. I worked carefully, and following the instructions I took about 10 minutes start to finish.
Immediately after unpacking the programmer I used the USB cable
to connect it to my computer and check for updates. The unit
automatically downloaded the most recent software and updated itself in
just a few minutes.

Uploading
the new tune to the truck was a very simple process. I must admit
that I am always a bit nervous at this point; I have never had an issue
while loading a tune but let's face it--you're messing with the
vehicle's brain here and I'd hate to suffer a failure during the
process. I connected the programmer to the OBD port (located
under the dash on the left side) via the supplied cable.

The
tuner came to life and instructed me to turn the ignition key to "on"
without starting the truck. It recognized the vehicle and showed
a menu page that gave me the options of downloading a new tune,
checking a diagnostic code, or data logging (to be used by a custom
tuner if you desire).

I
selected the tuning option and was taken to a menu of choices: 1) A
maximum performance tune that requires 93-octane fuel.
DiabloSport claims gains of 10 hp and 20 ft# torque. 2) an
87-octane tune for 5 hp and 15 ft# torque. 3) a max-mileage tune for
1-2 mpg gain over stock. 4) a custom option where you can modify
parameters for speed limiter, speedometer calibration, etc. All
of the choices give you the option of modifying the transmission's
shift firmness.

Since
I'm not looking for max performance I chose the 87-octane tune and
picked the option to make the transmission's shifts slightly firmer.
I followed the on-screen instructions carefully and the
programmer went to work. The first order of business was to save
a copy of the truck's stock tune. When this is done, it "locks" the
vehicle to that tuner and it can't be used on another vehicle unless
the first vehicle is returned to stock. Uploading the performance
tune and transmission tune took about 4-5 minutes. When it
was done I disconnected the cables, held my breath and turned the
igntion. It started! So far, so good--now for a test drive.

Results: As Advertised. The
improvement in throttle response was immediately obvious. Did I
gain 5 horsepower and 15 ft# torque? Don't know. I'm not
willing to spend $200-300 to dyno the truck before and after to be
scientific and the old butt-dyno is notoriously unreliable. My
Dad was an old-time hotrodder who owned a car repair business and he
called it the "gold factor": the more gold you spend on a
modification the more you want it to be faster. It certainly feels quicker, but that may be a result of the improved throttle response. I
also like the different transmission tuning. I had not found the
stock shifting to be objectionable, but I definitely like the firmer
shifts.

I
haven't had time to experiment with the 93-octane and max mileage
tunes, but will do so in the next few weeks and report on the results.

WORTH THE MONEY? I think so.Overall driveability is improved and the cost didn't break the bank. Looks like a good investment so far.

UPDATE: After
a few months, I decided the Diablo tune was a wash. It performed
as well as I had expected, but I finally decided to return the truck to
stock tune and sell the tuner on eBay. Here's why:

After
the novelty wore off I remembered the reason for buying the Colorado in
the first place: everyday transportation that could work on the ranch
and occasionally haul a stock trailer or hay trailer. It's not a
racer, and it would take a lote more than a downloaded tune to make it
one. To realize the full potential of the tune required premium
fuel and that got old quickly. In addition I didn't want the
hassle of a voided warranty on a truck that was less than a year old.
In other words, I decided to let the truck be a truck.